As industries look to produce products and packaging that contain certain percentages of recycled materials, your average water or beverage container has become the most viable plastic product on the market for recycling. But what about the cap?

Material recovery

Plastic bottle caps for beverages, or any other plastic containers, are typically made from a different type of plastic than the bottle itself. The caps on these containers are usually made from high-density polyethylene or polypropylene. For this reason, years ago, plastic recycling required you to remove caps to reduce contamination by keeping plastic types separate.

Sorting small items

Small items such as bottle caps are not accepted at most recycling facilities due to their size, so these plastic bottle caps were being lost in the trash with no hopes of material recovery. A good standard to sort by is that items smaller than a credit card should not go in your recycling bin. This is because most sorting machinery cannot identify or sort small items, so they end up discarded or, even worse, sent into the wrong batch of material.

Plastic pollution

With nearly 600 million plastic bottles and containers produced in a year, this could lead to innumerable plastic caps ending up in landfills, or worse, contributing to plastic pollution. A 2016 analysis of coastal plastic pollution by the North Sea Foundation found that plastic bottle caps are one of the top five littered items on beaches around the world.

The need for change

As the need for reducing plastic pollution grew and additional methods for recycling more plastics developed, the industry standard began to change. Now most recycling facilities in North America ask that caps are left on bottles and containers to collect the caps in an efficient manner.

There are a few reasons why these two different materials being kept together is no longer a problem. First, some sorting facilities will shred the plastic into small pieces. Then, while submerged in water, the PET will sink and the HDPE or polypropylene cap pieces will float, allowing it to be skimmed off the top and separated.

PET and HDPE or polypropylene also have different melting points, so the caps would melt away from the PET bottles before reaching their melting point, allowing the materials to separate naturally.

The Association of Plastic Recyclers has also determined that the marketability of plastic bales of bottles with caps on does not decrease the recyclability of either type of plastic and is helping to make it easier for residents to recycle both items if they are kept together.

Not every facility has changed their procedures and requirements for recycling yet. It is always important to check with your local facility to find out what their recycling requirements are regarding keeping caps on or off.

What about metal caps?

Some plastic bottles have caps with metal in them. What should you do with those? Unfortunately, these should not be kept on bottles because the metal will not sort out in the same way as plastic bottle caps. The metal will sink with the PET fragments and end up contaminating the entire plastic bale. Remove these metal caps and place them in the garbage, even if they have plastic on them as well.

You can always check with your local recycling facility to see if they have any alternative collection program for small metal caps such as these. There is a chance there could be a drop-off method, but if not, these are doomed to the landfill.

Keeping up with changes

The current standard is to keep your plastic bottle caps on beverage bottles and other plastic containers that are accepted for recycling in your area, but make sure your facility has updated this requirement before changing your ways. Even though there are constant advancements in recycling technologies, you need to follow the requirements of your specific recycling facility based on what machinery and methods they currently have.

It's always good to keep up with what new procedures your facility has established and if any additional materials are being added to the accepted list. Recycling procedures are not set in stone and vary greatly from location to location, so make sure you look up whatever items you are trying to recycle so that you help keep your program running efficiently and effectively.